Temperature-responsive device



P. H. BRACE TEMPERATURE RESPONSIVE DEVICE Filed Dec. 17, 1925 INVENTOR Puffer H. Brace.

WITNESSES:

Q7/WX f *flM -W ATTORNEY I Patented Dec. 18, 1928.-

UNITEDl'STAT-E' PATENT oF cs;

PORTER n. BRAGE, or WILKINSBUBG, PENNSYLVANIA, ASSIGNOR T0 wnscrmenousn ELECTRIC & MANUFACTURING COMPANY, A coRroRA'rIoN or PENNSYLVANIA.

TEMPEBATURE-RESPIONSIVE nnvrcnr Application filed necember v, 1925. SerialNo. 76,133.

My invention relates v to temperature responsive devices and particularly to devices that'are dependentupon the respective tem perature coefficients of the elastic moduli of a a f loys than those specified above, it'beinges the elements constituting such devices.

An object of my invention isto provlde a temperatureresponsive device that shall be operable in accordance with the internal stress variations in response to temperature variations and to external stresses applied thereto. a v c In practicing my inventiom'I provide, in general, a compound bar comprising a plurality of elemental bars joined gend-to-end.

I provide an arm member that is preferably located concentrically with the bar member at one of its ends and I provide also a frame in which the compound bar member is posi vtioned. The compound bar member is fixedly mounted at one end and adjustably mounted.

at the other end. I provide means at the adjustable end for applyinga twisting force or an external torque thereto in order that the bar shall be under a twisting strain in its operable position. Iv provide an electrical contact member on the movable arm which is mountedon the compound-bar and another contact member that is mounted onthe frame of the temperature responsive' device. The

contact members are so disposed that when 1 the bar has turned sufficiently, the contact memberswill engageto control an electric circuit. 3

In the accompanying drawings, 7 a Figure 1 is a plan view of a thermal responsive device embodying my invention,

Fig. 2 is a view in section of the device ile lustratedin Fig. 1 taken along the line Fig. 3 is a view in section of the device illustrated "in'Fig, 1 taken along the line,

III-III, v j c v c .3

Fig. 4 is a: view offa compound bar member employed in the device illustrated in Fig. 1 and I v Y Fig. 5 is a modification of the trated inFigs. '1, 2 and 3. ,7

Referring more particularly to i Fig. a

temperature responsive device 11com rises a compound bar"me nber"12and a" rame 13. Tl1e-compound bar member '12 comprises a bar 14 vof a desired metal and a bar 15 ofa suitably located in the frame 13 as illus- T trated in Fig. 1 in order that a suitable lever V r different-metal or alloy, the said bars 14'" and 15 being joined end-to-end at 16, preferably be of alumidevice num and the bar 15 of an alloy of Ni, Cr., and iron; I

It is. to be understood that the'bars 14:

and 15 may be made of other metals and alsential that the moduli of elasticity of'theh respective bars employed be, different and that the rate of change-in the modulus of elasticity of one bar with respect to the other be greater per degree change in temperature thereof. The rate of change in the elastic modulus of elasticity per degree-change temperature may be denominated as the temopening22. The sides 18 and 21 have openings 23' and,24, respectively, located in substantially the central portion of the respec tive sidesimentioned. A pin hole 25 is provided inthe side 21 and a similar hole 26' havingscrew threads 27 located therein is provided inthe side 18. I

The compound bar member has a pinhole compound bar 12., The end of the portion-14 28 located at the end of the portion 15 of the of the compound bar 12 is provided with a tion 31.: 'A nut member 32 is provided to regthreaded portion 29 and a square end por- 8b ister with the threaded portion 29 of the por- 1 tion 14 of the compound bar 12. The bar 12 is also. provided with a contact arm 33 which is preferably shrunk on the bar member12 ,at 'the'welded junction 16. An adjustable contact screw 34 is provided at the free end 35 of the contact arm 33 and isinsulated from the contact arm 33. A stationary contact member 36 is provided on the frame 13 and is insulated therefrom. The contact' member 36 is suitably located on'the side 19 of the frame 13 in order that, when the contact arm 33 is turned, the contact membersw 34 and 36 will engage to complete an electric circuit 37.

The compound bar member l2 is located inthe. holes 23 and 24-of the frame 13. A 7

pin member 38 is provided 1 that registers with the coaxial holes 28. and25 of the frame side 211andjthe bar 'portion15 of the com,- pound bar member 12. a The threaded end'of the portion 14 of the compound bar 12 is (not shown) may be applied to the portion the'fixedend oi the bar 12 illustrated in ascrew members (not shown) that correspond Cit Fig. 1. v V

As previously mentioned hereimthe bar I 14.0f the compound bar 12 may beof such material as aluminum, and the bar 150i an 31, whereby the bar 12 may be twisted in such direction that the contact members and 36 will be disengaged. The nut 32 is then vanced on the threaded portion 29, suiliciently against the member 18-to hold the co v pound bar 12in its twisted position. To further secure the bar 12 in its twis' position, I provide a set screw 39 th registers with a threaded portion 30 of the hole 26 gages the bar member 14.

In Fig. 5, I have shown a modification 0i the device illustrated in Fig. 1. I have pro vided in this modified form of my device a pair of compound bar members-41 and 42 that are similar to the compound bar 12 illustratedin Figs. 1' to 4. The frame structure 43 is'substantially the same as the frame '13 illustrated in Fig. 1. The compound bars 41 and 42 are held at the lixed end by pin meinbersr38, the same as are used in holding also provide a'pinioii 46 that is mounted on a shaft 47 which-is free to turn inbearin f D provided therefor. 48 is attached to the shaft 47 for indicating any movement thereof on a suitablescale. Y The number of teeth in the gear-wheels 45 is preferably much larger than that of the teeth in thepinion 46 in orderthat any turn iiig motion of the bars 41 and 42 maybe multiplied many times to produce arela tively large movement of the pointer 48. Tn order that the bars 41 and 42 will both'impart the same direction of motion to the pinion 46, they'must, therefore, be. twisted in the same direction. It thefdesired external torque has been applied to the square portions 44 of the bars 41 and 42, the barsmay then be held in their twisted position by with the screw member 89 illustrated in alloy containing 22% Ni, 3% Cr. and iron,

although minor quantities of other metals and impurities maybe addedif so desired.

The modulus of elasticity of the b'ar'14,

being of aluminum, is different-from that of the bar 15, it being an alloy having preterablya higher modulus of elasticity. It the temperature of the bar 14 is increased its) modulus of elasticity decreases, but at a higher rate than the rate of decrease in the modulus of elasticity of the bar 15 for come- I sponding increases in temperature.

An indicating 1' member The compound bar 12 is'twisted a predel termined amount by applying a twisting or turning force to the portion 31 thereof. Thus, the members or bars 14 and 15- are subthroughout their lengths. i ;.llieop erat1on ofmy device is substantially as follows: The temperature responsive device 1 1 is locatedwith in a body or chamber,

the temperature of which is to be regulated. 11 the temperature of the twisted "1S ected to altorsional stress that is distributed increased to a predetermined value, theela'sticf modulusofelastic t of the bar 15 will def" crease 'ino'r'e rapidly than thatot the bar'1-4, and, since the torsional stress at all points oi the: bar 12 must remain equahthetbar 15 will betwisted in a direction thatptends to increase the 1 torsional "stresses therein.

Therefore, the bar 14 will twist or-' turn cor respo'ndingly in a d rection that tendsto decrease the torsional stresses to which it is sub- 1 jected. Thus,the bars 14 andlfi will twist or turn together to such a positionth-atthef' torsional stresses eiristi-n in the com sound bar 12 have again become stabilized and unitorin throu hout its len th The twistingof thebar to the above position is utilized to f move the contact 34 carried by the arm 38 into engagement with the stationary contact 85, thereby energizing tne electric circuit 3 lit the temperature of the compound bar'is reduced to value below that referred to above, the elastic moduli of therespective bars '14 and 15 will incrcase but at unequal rates, thus effecting a turning or twisting. of

the oompoundbar 12 to such apositionthat the arm 33 is actuated to cause disengage-L of heat, to which the compound bar 12 is ment or the contact from itscooperating; v, cont-act 36, thereby deen'ergizing the electric circuit 87'. It may be assumed that a source.

subjectiech'is deenergi ed when the contact are out of engagement with each other.

The temperature difference required for" the operation of my device may be made-reletively small by making'the ratio,

. length to diameter of the. bar 12, large- In Figs. 1 2 and 3, I haveishown the tein- .meinbers 34 and 36 are in engagement, and reenergized when the said contact members perature responsive device as controlling electric circuitbut obviously the device neet not necessarily control anele'ctric' circuit for" it may be used as an indicating device as; illustrated in Fig. '5or it"may' beused ior actuating, in general, any suitable device. Various modifications may bemade withand the scope out-departing from the spin Y I oit'my'in'vention; I, therefore, desirerthat only such limitationsshall be placed thereon as are imposedby the prior art.

I claim as my invention:

1. In a --temperature responsive device, in combinat on, actuable means, a bimetal mem-;

ber disposed to actuate said actuable means,

means for applying a predetermined torque to said bimetal member, said bimetal member being responsive to said torque upon changes in temperature thereof to cause a twisting action for actuating said actuable means.

2. In a temperature responsive device, in combination, actuable means, a bimetal member, means forapplying a torque of a predetermined value to said bimetal member, said bimetal member being responsive to said torque upon changes in temperature thereof .to causea twisting action,'and means associated with said bimetal member adapted to utilize said turning action for actuating said actuable means. i

3. In a temperatureresponsive device, in combination, actuable means, and means comprising a bimetal member, the individual metals of which have a definite ratio of elastic modulus at a predetermined temperature,

means for applying a torque of a predeten mined value to said bimetal member, said bimetal member being responsive to said torque to cause a twisting action thereof for actuatQ ing said actuable means upon a change in said ratio of elastic modulus effected by a change in said predetermined temperature.

4. A temperature responsive device comprising alined members, joined at their ends only, and means for applying a torsional force thereto, said members being adapted to yield in response to said force in accordance with variations in the ratio of the elastic moduli of said members when subjected to temperature variations,

5. A temperature responsive device comdifferent moduli of elasticity, means for holding one end of each of said bar members fixed and means for applying a predetermined torque to the other ends thereof, said com pound bar members being actuated in accordance with the torque applied thereto and the variations in the moduli of elasticity of said bar members in response to temperature variations.

1 7. In a temperature responsive device, in

combination, actuated means, a pair of parallel compound bars, each of said bars having a pair of elements joined end to end, the elements thereof having'difi'erent temperature coeiiicients of elastic moduli, means for holding said compound parallel bars in a twisted position, said bars being adapted to turn towards an untwisted position upon changes in the elastic moduli thereof in response to tem-' perature variations, and means associated -With said bars for multiplying the untwisting motion thereof for actuating said actuated means;

8. In a temperature responsive device comprising a pair of parallel compound bars, eachof said bars having a pair of bars joined end to end, said bars having different temperature coefiicients of elastic moduli, means for applying a torque'to said bars and for holding the same under the stress thereof, said bars being adapted to turn in accordance with changes in the elastic moduli thereof in responseto temperature variations and to the torque applied thereto, and means associated therewith for multiplying said turning motion. I

9. A temperature responsive device comprising a pair of parallel compound bars, each of said bars having a pairof bars joined end to end having a gear mounted on each of said compound bars, said bars having different temperature coefiicients of elastic moduli, and a pinion pivotally mounted in common relation to said gears formultiplying the turning motion of said compound bars.

10. In a temperature-responsive device, in combination, a metallic rod, and means for applying a torsional force to said rod, said torsional force being effective to cause said rod to twist in accordance with changes in'the elastic modulus thereof responsive to changes in temperature. 1

In testimony whereof, I have hereunto subscribed my name this 7th day of December,

PORTER H. Barton. 

